Avoiding nocturnal hypoglycaemia in children

Closed-loop systems that link continuous glucose measurements to insulin delivery could reduce risk of nocturnal hypoglycaemia in children and adolescents with type I diabetes, new research has found.
A team led by Dr Roman Hovorka of the Institute of Metabolic Science, University of Cambridge, undertook three randomised crossover studies in 19 patients aged five to 18 years with type I diabetes of duration 6·4 years.

Standard continuous subcutaneous insulin infusion was compared with closed-loop delivery (n=13; APCam01); closed-loop delivery after rapidly and slowly absorbed meals (n=7; APCam02); and closed-loop delivery and standard treatment after exercise (n=10; APCam03). In APCam01, investigators were masked to plasma glucose.
During closed-loop nights, glucose measurements were fed every 15 minutes into a control algorithm calculating rate of insulin infusion, and a nurse adjusted the pump. During control nights, standard pump settings were applied. Primary outcomes were time for which plasma glucose concentration was 3·91—8·00 mmol/L or 3·90 mmol/L or lower.
Some 17 patients were studied for 33 closed-loop and 21 continuous infusion nights.
Primary outcomes did not differ significantly between treatment groups in APCam01 (12 analysed; target range, median 52 per cent [IQR 43—83] closed loop vs 39 per cent [15—51] standard treatment, p=0·06; ≤3·90 mmol/L, 1 per cent [0—7] vs 2 per cent [0—41], p=0·13), APCam02 (six analysed; target range, rapidly 53 per cent [48—57] vs slowly absorbed meal 55 per cent [37—64], p=0·97; ≤3·90 mmol/L, 0 per cent [0—4] vs 0 per cent [0—0], p=0·16]), and APCam03 (nine analysed; target range 78 per cent [60—92] closed loop vs 43 per cent [25—65] control, p=0·0245, not significant at corrected level; ≤3·90 mmol/L, 10 per cent [2—15] vs 6 per cent [0—44], p=0·27).
A secondary analysis of pooled data documented increased time in the target range (60 per cent [51—88] vs 40 per cent [18—61]; p=0·0022) and reduced time for which glucose concentrations were 3·90 mmol/L or lower (2·1 per cent (0·0—10·0) vs 4·1 per cent (0·0—42·0); p=0·0304).
No events with plasma glucose concentration lower than 3·0 mmol/L were recorded during closed-loop delivery, compared with nine events during standard treatment.
The Lancet, Volume 375,
Issue 9716, Pages 743-751, 27 February 2010.